1. Field of the Invention
The present invention relates to systems for detecting unauthorized tampering with a device, and, more particularly, to systems for detecting unauthorized tampering with a device that is disposed within an enclosure.
2. Description of the Related Art
Many devices must be placed in locations where they may be exposed to unauthorized tampering or theft. Such devices include controllers for telephone systems, alarm systems, cable television systems, firearms, art work and other valuables, for example. In order to protect the devices from tampering and other forms of physical harm, they may be placed within security system enclosures in the form of boxes that are attached to fixed structures such as ceilings, walls, floors and posts. The boxes may have hinged covers for enabling authorized access to the devices within the boxes, and theses doors may be locked shut.
The security system enclosures commonly employ tamper switches for detecting that the cover of the enclosure has been opened, or that the enclosure has been removed from the fixed structure to which it was attached. A typical tamper switch has a pair of contacts that may be opened or closed as a result of the enclosure door being opened, or as a result of the enclosure being removed from the fixed structure. A problem, however, is that separate switches must be used for detecting the opening of the door and the removal of the enclosure from the fixed structure. That is, one tamper switch may detect the opening of the door, and a separate tamper switch may be required to detect the removal of the enclosure from the wall. The use of two separate switches adds to the cost and increases the size of the tamper detection system.
What is needed in the art is a tamper switch arrangement that utilizes a single tamper switch to detect both the opening of a door of the security system enclosure and the removal of the enclosure from the fixed structure on which it is mounted.